Resonance Raman spectroscopy has been combined with the electric voltage control techniques developed in this laboratory to add a new dimension to the potentiometric characterization of cytochrome aa3. This new approach confirms the existence (previously established in this laboratory) of a low potential species of cytochrome a3 (Em=200 mV), and of two forms of cytochrome a (Em's of 260 and 340 mV). In addition, a new form of cytochrome a3 (Em=approximately 260 mV) has been found. The technique also showed that the absorbance at 830 nm is not a unique monitor for CuA, as has been assumed. The new ultrarapid spectrometer, under development in the laboratory, has been completed. Preliminary studies on the reduction of cytochrome aa3 by cytochrome c, indicate a more complicated series of electron transfer events than are currently believed. Two distinct kinetic forms of the enzyme can be observed depending on the presence or absence of a small amount of O2. Multichannel studies on the laser- activated photocycle of bacteriorhodopsin have been initiated. The kinetic spectra obtained have been deconvoluted by SVD and it has been confirmed that the level of laser activation does influence the kinetics of the ensuing photocycle, changing the relative weights of key intermediates. A new optical bench setup has been constructed that vastly improves the sensitivity of the system, allowing for a very low level of monitoring light, and having the ability to detect absorbance changes in the submilli-O.D. range.